Liquid hardening

ABSTRACT

Curing agents for air-drying alkyd-based resins, coatings, such as paint, varnish or wood stain, inks and linoleum floor coverings, based on an iron/manganese complex containing tetradentat, pentadentate or hexadentate nitrogen donor ligands are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Application No. 12/309,051,filed Jan. 5, 2009 which is the U.S. National Phase under 35 U.S.C. §371of International Application PCT/EP2007/056557, filed Jun. 29, 2007,which claims priority to EP 06253591.9, filed Jul. 7, 2006.

FIELD OF INVENTION

The present invention concerns the curing and hardening of liquids. Inparticular the present invention relates to the curing and hardening ofinks and paints.

BACKGROUND OF INVENTION

Recent reviews describe different alternatives, especially based on Mnand Fe compounds (Bieleman, J. H. in Additives in Plastics and Paints,Chimia, 56, 184 (2002); Bieleman, J. H., Marcomol. Symp., 187, 811(2002); van Gorkum R, Bouwman E, Coord. Chem. Rev., 249, 1709 (2005)).

WO 03/093384 describes the use of transition-metal salts or complexesbased on pyrazoles, aliphatic and aromatic amines, 2,2′-bipyridine,1,10′-phenanthroline, 1,4,7-trimethyl-1,4,7-triazacyclononane incombination with a reducing agent as drying agent. Especially Fe and Mnsalts and complexes were preferred in combination with ascorbic acid orderivatives thereof. WO03/093384 demonstrates that iron compounds have arather poor activity and hence high dosages are needed to getsatisfactory drying activity. A drawback of using iron compounds at highlevels is that an unwanted yellowish/brownish colour is imparted to themix.

SUMMARY OF INVENTION

The present invention concerns settable liquid compositions that containa siccative and an alkyd-based resin. The siccative is the component ofthe liquid composition that facilitates drying, curing, setting, orhardening of the composition.

The liquid may be any settable liquid, for example, lacquer, inks andpaints. The term paint includes lacquers. The term alkyd-based resingenerally refers to polyesters modified with fatty acids. Alkyd-basedresins are generally prepared via the condensation polymerisationreaction of three types of monomers: polyalcohols, polybasic acids andfatty acids or triglyceride oils.

We have found active iron and manganese compounds that are active as asiccative at relatively low concentrations.

In one aspect the present invention provides a curable liquid mediumcomprising:

-   a) from 1 to 90 wt %, preferably from 20 to 70 wt %, of an    alkyd-based resin; and,-   b) from 0.0001 to 0.1 wt % of a siccative, wherein the siccative is    an iron or manganese complex of a tetradentate, pentadentate or    hexadentate nitrogen donor ligand; the tetradentate, pentadentate or    hexadentate nitrogen donor ligands are described in detail below.

Preferably the iron or manganese complex is of a tetradentate orpentadentate nitrogen donor ligand. More preferably the iron compoundcontains a pentadentate nitrogen donor ligand and the manganese compounda tetradentate nitrogen donor ligand.

In another aspect the present invention provides the composition of thepresent invention after curing.

DETAILED DESCRIPTION OF INVENTION

The present invention relates to a siccative for alkyd-based resins,coatings, inks, and linoleum floor coverings, comprising an iron ormanganese complex containing a tetradentate, pentadentate or hexadentatenitrogen donor ligand. Whilst certain paints/inks contain unsaturatedoils/acids as cross-linking agent, most of them contain alkyd-basedresins that contain unsaturated groups. The alkyd-based air-dryingcoatings to which the siccative of the present invention can be added,comprise coatings, such as paint, varnish or wood stain, and alsoincludes inks and linoleum floor coverings and the like. The siccativeis equally applicable to setting paints/inks/print which do not containalkyd-based resins, but do contain at least 2% of double or tripleunsaturated compound.

The coatings, inks, and linoleum floor coverings may also includecompositions wherein besides the alkyd based binder also other bindersare present, e.g. compositions comprising 1) an alkyd-based binder and2) a polyacrylate and/or a polyurethane binder. Conventional air-dryingalkyds can be obtained by a polycondensation reaction of one or morepolyhydric alcohols, one or more polycarboxylic acids or thecorresponding anhydrides, and long chain unsaturated fatty acids oroils.

Due to its presence in naturally occurring oils, glycerol is a widelyencountered polyol. Other examples of suitable polyhydric alcoholsinclude: pentaerythritol, dipentaerythritol, ethylene glycol, diethyleneglycol, propylene glycol, neopentyl glycol, trimethylol propane,trimethylol ethane, di-trimethylol propane and 1,6-hexane diol.Polycarboxylic acids and the corresponding anhydrides, used tosynthesise alkyds, comprise aromatic, aliphatic and cycloaliphaticcomponents, which are generally derived from petrochemical feedstocks.Typical examples of such polyacids include: phthalic acid and itsregio-isomeric analogues, trimellitic acid, pyromellitic acid, pimelicacid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acidand tetra-hydrophthalic acid.

Suitable drying fatty acids, semi-drying fatty acids or mixture thereof,useful herein, are ethylenically unsaturated conjugated ornon-conjugated C₂-C₂₄ carboxylic acids, such as oleic, ricinoleic,linoleic, linolenic, licanic acid and eleostearic acids or mixturethereof, typically used in the form of mixtures of fatty acids derivedfrom natural or synthetic oils. By semi-drying and drying fatty acids ismeant fatty acids that have the same fatty acid composition as the oilsthey are derived from. The classfication of the oils is based on theiodine number; for drying oil the iodine number is >140; for semi-dryingoil the iodine number is ranging between 125 and 140, and for non-dryingoil the iodine number is <125 (“Surface Coatings”, by Swaraj Paul, JohnWiley and Sons; p. 89). Suitable organic solvents to dilute theair-drying alkyds of the invention include aliphatic, cycloaliphatic andaromatic hydrocarbons, alcohol ethers, alcohol esters andN-methylpyrrolidone. However it may also be an aqueous carriercontaining the alkyd resin in the form of an emulsion and a suitableemulsifier as is well known in the art.

An ink of the present invention containing an alkyd varnish, modifiedwith unsaturated fatty acids, as defined above, as a vehicle componentof the ink is usable, but not limited to, as a metal plate ink,lithographic ink, relief printing ink, screen ink or offset overprintingink.

The siccative will preferably be partly or completely dissolved in thealkyd resin, emulsion etc. The catalytic activity of the transitionmetal ion depends upon the ion itself and on the type of ligandsemployed, as disclosed herein. The siccative may also be dosed to thecomposition just prior the use of the composition.

The composition of the present invention can, if desired or ifnecessary, also comprise other additives such as other siccatives.

The invention is also an air-drying alkyd-based coating, resin, ink, orfloor covering comprising a siccative according to the invention, e.g.containing from 0.00001 to 0.1 wt % (based on the amount of binder; thiswill be generally 5 to 50 times higher than when metal-based, dependingon the molecular weight of the compound defined herein) of the iron ormanganese complex containing a tetradentate, pentadentate or hexadentatenitrogen donor. The air-drying alkyd-based coating, resin, ink, or floorcovering may further comprise a polyacrylate and/or a polyurethanebinder.

The composition of the present invention may contain colourants,pigment, anti-corrosive pigment, and/or extender pigment and/or a dye.It may further contain, if necessary, plasticizer, surface-controllingagents, anti-silking agent, a defoaming agent, a rheological controllingagent and/or an ultraviolet absorber.

The addition of the siccative itself is done with conventionaltechniques, known to the person skilled in the art. The siccative iseither added during the production of the alkyd based resins, coatings,inks, and linoleum floor coverings, or is added under stirring to thembefore use.

The composition of the present invention is preferably stored under aninert atmosphere, for example nitrogen or carbon dioxide.

Stability Agents

The composition of the present invention preferably comprises anantioxidant in the range 0.001% to 0.1%, most preferably 0.002 and0.05%. Suitable antioxidants are disclosed in U.S. Pat. No. 6,586,383.Most preferably the antioxidant is selected from the group consistingof: di-tert-butyl hydroxy toluene, ethoxyquine, α-tocopherol, and6-hydroxy-2,5,7,8-tetra-methylchroman-2-carboxylic acid.

The composition of the present preferably comprises ethyleneglycoland/or glycerol in the range 0.1 and 50 wt %, preferably 0.3 and 5 wt %.

Siccative

Preferably, the siccative is present in the a curable liquid medium from0.0001 and 0.1% w/w, more preferably from 0.001 and 0.1% w/w and mostpreferably from 0.002 and 0.05% w/w.

The tetradentate, pentadentate or hexadentate nitrogen donor ligand maybe built up within any organic structure which will support coordinatingnitrogen atoms. For example one can take a basic tridentate ligand suchas 1,4,7-triazacyclononane and have further nitrogen co-ordinationgroups, e.g., —CH2—CH2—NH2, —CH2-Py, covalently bound to one or more ofthe cyclic nitrogens or aliphatic groups.

Preferably the iron ion is selected from Fe(II) and Fe(III) and themanganese ion is selected from Mn(II), Mn(III), and Mn(IV).

Preferably the ligand is present in one or more of the forms [MnLCl₂];[FeLCl₂]; [FeLCl]Cl; [FeL(H₂O)](PF₆)₂; [FeL]Cl₂, [FeLCl]PF₆ and[FeL(H₂O)] (BF₄)₂.

The following are preferred classes of siccative that are iron ormanganese complexes of tetradentate, pentadentate or hexadentatenitrogen donor ligands.

If unspecified the length of any alkyl chain is preferably C1 toC8-alkyl chain and preferably linear. If unspecified the aryl group is aphenyl group.

Bispidon

The bispidon class are preferably in the form of an iron transitionmetal catalyst.

The bispidon ligand is preferably of the form:

wherein each R is independently selected from: hydrogen, F, Cl, Br,hydroxyl, C1-C4-alkylO—, —NH—CO—H, —NH—CO—C1-C4-alkyl, —NH2,—NH—C1-C4-alkyl, and C1-C4-alkyl;

-   R1 and R2 are independently selected from:-   C1-C24-alkyl,-   C6-C10-aryl, and,-   a group containing a heteroatom capable of coordinating to a    transition metal;-   R3 and R4 are independently selected from hydrogen, C1-C8 alkyl,    C1-C8-alkyl-O—C1-C8-alkyl, C1-C8-alkyl-O—C6-C10-aryl, C6-C10-aryl,    C1-C8-hydroxyalkyl, and —(CH2)_(n)C(O)OR5-   wherein R5 is independently selected from: hydrogen, C1-C4-alkyl, n    is from 0 to 4, and mixtures thereof; and,-   X is selected from C═O, —[C(R6)₂]_(y)— wherein Y is from 0 to 3 each    R6 is independently selected from hydrogen, hydroxyl, C1-C4-alkoxy    and C1-C4-alkyl.

Preferably R3=R4 and selected from —C(O)—O—CH3, —C(O)—O—CH2CH3,—C(O)—O—CH2C6H5 and CH2OH.

Preferably the heteroatom capable of coordinating to a transition metalis pyridin-2-ylmethyl optionally substituted by —C0-C4-alkyl.

Preferably X is C═O or C(OH)2.

Preferred groups for R1 and R2 are CH3, —C2H5, —C3H7, benzyl, —C4H9,—C6H13, —C8H17, —C12H25, and —C18H37 and pyridin-2-yl. A preferred classof bispidon is one in which at least one of R1 or R2 ispyridin-2-ylmethyl or benzyl, preferably pyridin-2-ylmethyl.

A preferred bispidon is dimethyl2,4-di-(2-pyridyl)-3-methyl-7-(pyridin-2-ylmethyl)-3,7-diaza-bicyclo[3.3.1]nonan-9-one-1,5-dicarboxylate(N2py3o-C1) and the iron complex thereof. FeN2py3o-C1 which was preparedas described in WO02/48301. Other preferred bispidons are one in whichinstead of having a methyl group (C1) at the 3 position have longeralkyl chains, namely isobutyl, (n-hexyl) C6, (n-octyl) C8, (n-dodecyl)C12, (n-tetradecyl) C14, (n-octadecyl) C18, which were prepared in ananalogous manner.

Preferred tetradentate bispidons are also illustrated in WO00/60045 andpreferred pentadentate bispidons are illustrated in WO02/48301 andWO03/104379.

N4py Type

The N4py are preferably in the form of an iron transition metalcatalyst.

The N4py type ligands are preferably of the form:

wherein

-   -   each R¹, R² independently represents —R⁴—R⁵,    -   R³ represents hydrogen, optionally substituted alkyl, aryl or        arylalkyl, or —R⁴—R⁵,    -   each R⁴ independently represents a single bond or optionally        substituted alkylene, alkenylene, oxyalkylene, aminoalkylene,        alkylene ether, carboxylic ester or carboxylic amide, and    -   each R⁵ independently represents an optionally N-substituted        aminoalkyl group or an optionally substituted heteroaryl group        selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl,        imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and        thiazolyl.

Preferably R¹ represents pyridin-2-yl or R² representspyridin-2-yl-methyl. Preferably R² or R¹ represents 2-amino-ethyl,2-(N-(m)ethyl)amino-ethyl or 2-(N,N-di(m)ethyl)amino-ethyl. Ifsubstituted, R⁵ preferably represents 3-methyl pyridin-2-yl. R³preferably represents hydrogen, benzyl or methyl.

The preferred ligands are N4Py (i.e. N,N-bis(pyridin-2-yl-methyl)-bis(pyridin-2-yl)methylamine) which isdisclosed in WO95/34628 and MeN4Py (i.e. N,N-bis(pyridin-2-yl-methyl)-1,1 -bis(pyridin-2-yl)- 1- aminoethane, as disclosed in EP 0909809.

TACN-Nx

The TACN-Nx are preferably in the form of an iron transition metalcatalyst.

The ligands possess the basic 1,4,7-triazacyclononane structure but haveone or more pendent nitrogen groups that complex with the transitionmetal to provide a tetradentate, pentadentate or hexadentate ligand.Preferably, the basic 1,4,7-triazacyclononane structure has two pendentnitrogen groups that complex with the transition metal (TACN-N2). TheTACN-Nx is preferably of the form:

wherein each R20 is selected from: an alkyl, cycloalkyl,heterocycloalkyl, heteroaryl, aryl and arylalkyl groups optionallysubstituted with a substituent selected from hydroxy, alkoxy, phenoxy,carboxylate, carboxamide, carboxylic ester, sulphonate, amine,alkylamine and N⁺(R21)₃, wherein R21 is selected from hydrogen, alkanyl,alkenyl, arylalkanyl, arylalkenyl, oxyalkanyl, oxyalkenyl, aminoalkanyl,aminoalkenyl, alkanyl ether, alkenyl ether, and —CY₂—R22, in which Y isindependently selected from H, CH3, C2H5, C3H7 and R22 is independentlyselected from an optionally substituted heteroaryl group selected frompyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl,pyrimidinyl, triazolyl and thiazolyl; and wherein at least one of R20 isa —CY₂—R22.

Preferably R22 is selected from optionally substituted pyridin-2-yl,imidazol-4-yl, pyrazol-1-yl, quinolin-2-yl groups. Most preferably R22is either a pyridin-2-yl or a quinolin-2-yl.

Cyclam and Cross Bridged Ligands

The cyclam and cross bridged ligands are preferably in the form of amanganese transition metal catalyst.

The cyclam ligand is preferably of the form:

wherein: Q is independently selected from:

p is 4;

R is independently selected from: hydrogen, C1-C6-alkyl, CH2CH2OH,pyridin-2-ylmethyl, and CH2COOH, or one of R is linked to the N ofanother Q via an ethylene bridge;

R1, R2, R3, R4, R5 and R6 are independently selected from: H,C1-C4-alkyl, and C1-C4-alkylhydroxy.

Preferred non-cross-bridged ligands are1,4,8,11-tetraazacyclotetradecane (cyclam),1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (Me4cyclam),1,4,7,10-tetraazacyclododecane (cyclen),1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane (Me4 cyclen), and1,4,7,10-tetrakis(pyridine-2-ylmethyl)-1,4,7,10-tetraazacyclododecane(Py4 cyclen). With Py4 cyclen the iron complex is preferred.

A preferred cross-bridged ligand is of the form:

wherein “R¹” is independently selected from H, and linear or branched,substituted or unsubstituted C1 to C20 alkyl, alkylaryl, alkenyl oralkynyl; and all nitrogen atoms in the macropolycyclic rings arecoordinated with the transition metal.

Preferably R1=Me, which is the ligand5,12-dimethyl-1,5,8,12-tetraaza-bicyclo[6.6.2]hexadecane of which thecomplex [Mn(Bcyclam)Cl₂] may be synthesised according to WO98/39098.

Other suitable crossed bridged ligands are also found in WO98/39098.

TRISPICEN-type

The trispicens are preferably in the form of an iron transition metalcatalyst.

The trispicen type ligands are preferably of the form:R17R17N—X—NR17R17  (VI),wherein:

-   -   X is selected from —CH2CH2—, —CH2CH2CH2—, —CH2C(OH)HCH2—; and,    -   R17 independently represents a group selected from: R17 and        alkyl, cycloalkyl, heterocycloalkyl, heteroaryl, aryl and        arylalkyl groups optionally substituted with a substituent        selected from hydroxy, alkoxy, phenoxy, carboxylate,        carboxamide, carboxylic ester, sulphonate, amine, alkylamine and        N⁺(R19)₃, wherein R19 is selected from hydrogen, alkanyl,        alkenyl, arylalkanyl, arylalkenyl, oxyalkanyl, oxyalkenyl,        aminoalkanyl, aminoalkenyl, alkanyl ether, alkenyl ether, and        —CY₂—R18, in which Y is independently selected from H, CH3,        C2H5, C3H7 and R18 is independently selected from an optionally        substituted heteroaryl group selected from pyridinyl, pyrazinyl,        pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl,        triazolyl and thiazolyl; and wherein at least two of R17 are        —CY₂—R¹⁸.

The heteroatom donor group is preferably pyridinyl optionallysubstituted by —C0-C4-alkyl.

Other preferred heteroatom donor groups are imidazol-2-yl,1-methyl-imidazol-2-yl, 4-methyl-imidazol-2-yl, imidazol-4-yl,2-methyl-imidazol-4-yl, 1-methyl-imidazol-4-yl, benzimidazol-2-yl and1-methyl-benzimidazol-2-yl.

Preferably three of R17 are CY₂—R18.

The ligand Tpen (i.e.N,N,N′,N′-tetra(pyridin-2-yl-methyl)ethylenediamine) is disclosed inWO97/48787.

The following are preferred trispicens:N-methyl-tris(pyridin-2-ylmethyl)ethylene-1,2-diamine;N-octyl-tris(pyridin-2-ylmethyl)ethylene-1,2-diamine;N-octadecyl-tris(pyridin-2-ylmethyl)ethylene-1,2-diamine;N-methyl-N,N′,N′-tris(3-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-ethyl-N,N′,N′-tris(3-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-methyl-N,N′,N′-tris(5-methyl-pyridin-2-ylmethyl)ethyl ene-1,2-diamine;N-ethyl-N,N′,N′-tris(5-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-benzyl-N,N′,N′-tris(3-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-benzyl-N,N′,N′-tris(5-methyl-pyridin-2-ylmethyl)ethyl ene-1,2-diamine;N-butyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethyl ene-1,2-diamine;N-octyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethyl ene-1,2-diamine;N-dodecyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethyl ene-1,2-diamine;N-octadecyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethyl ene-1,2-diamine;N-Methyl-N,N′,N′-Tris(imidazol-2-ylmethyl)-ethylenediamine;N-ethyl-N,N′,N′-Tris(imidazol-2-ylmethyl)-ethylenediamine;N,N′-dimethyl-N,N′-bis(imidazol-2-ylmethyl)-ethylenediamine;N-(1-propan-2-ol)-N,N′,N′-Tris(imidazol-2-ylmethyl)-ethylenediamine;N-(1-propan-2-ol)-N,N′,N′-Tris(1-methyl-imidazol-2-ylmethyl)-ethylenediamine;N,N-diethyl-N′,N″,N″-Tris(5-methyl-imidazol-4-ylmethyl)-diethylenetriamine;N-(3-propan-1-ol)-N,N′,N′-Tris(1-methyl-imidazol-2-ylmethyl)-ethylenediamine;N-hexyl-N,N′,N′-Tris(imidazol-2-ylmethyl)-ethylenediamine;N-methyl-N,N′,N′-tris(benzimidazol-2-ylmethyl)-ethylenediamine; and,N-(3-propan-1-ol)methyl-N,N′,N′-tris(benzimidazol-2-ylmethyl)-ethylenediamine.

Other suitable trispicens are found in WO02/077145.

Of the non-bispidon type siccatives the following are most preferred:

5,12-dimethyl-1,5,8,12-tetraaza-bicyclo[6.6.2]hexadecane,5,12-dibenzyl-1,5,8,12-tetraaza-bicyclo[6.6.2]hexadecane,1,4,8,11-tetraazacyclotetradecane,1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane,1,4,7,10-tetraazacyclododecane,1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane, and1,4,7,10-tetrakis(pyridine-2ylmethyl)-1,4,7,10-tetraazacyclododecane,N,N-bis(pyridin-2-yl-methyl)-bis(pyridin-2-yl)methylamine,N,N-bis(pyridin-2-yl-methyl)-1,1-bis(pyridin-2-yl)-1-aminoethane,N,N,N′,N′-tetra(pyridin-2-yl-methyl)ethylenediamine,N-methyl-tris(pyridin-2-ylmethyl)ethylene-1,2-diamine;N-butyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethylene-1,2-diamine;N-octyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethylene-1,2-diamine;N-dodecyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethylene-1,2-diamine;N-octadecyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethylene-1,2-diamine;N-methyl-N,N′,N′-tris(3-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-ethyl-N,N′,N′-tris(3-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-methyl-N,N′,N′-tris(5-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-ethyl-N,N′,N′-tris(5-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-benzyl-N,N′,N′-tris(3-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-benzyl-N,N′,N′-tris(5-methyl-pyridin-2-ylmethyl)ethylene-1,2-diamine;N-methyl-N,N′,N′-tris(imidazol-2ylmethyl)-ethylenediamine;N-ethyl-N,N′,N′-tris(imidazol-2ylmethyl)-ethylenediamine;N,N′-dimethyl-N,N′-bis(imidazol-2-ylmethyl)-ethylenediamine;N-(1-propan-2-ol)-N,N′,N′-tris(imidazol-2ylmethyl)-ethylenediamine;N-(1-propan-2-ol)-N,N′,N′-tris(1-methyl-imidazol-2ylmethyl)-ethylenediamine;N,N-diethyl-N′,N″,N″-tris(5-methyl-imidazol-4ylmethyl)-diethylenetriamine;N-(3-propan-1-ol)-N,N′,N′-tris(1-methyl-imidazol-2-ylmethyl)-ethylenediamine;N-hexyl-N,N′,N′-tris(imidazol-2ylmethyl)-ethylenediamine;N-methyl-N,N′,N′-tris(benzimidazol-2ylmethyl)-ethylenediamine; and,N-(3-propan-1-ol)methyl-N,N′,N′-tris(benzimidazol-2ylmethyl)-ethylenediamine;1,4-bis(quinolin-2-ylmethyl)-7-octyl-1,4,7-triazacyclononane;1,4-bis(quinolin-2-ylmethyl)-7-ethyl- 1,4,7-triazacyclononane;1,4-bis(quinolin-2-ylmethyl)-7-methyl-1,4,7-triazacyclononane;1,4-bis(pyridyl-2-methyl)-7-octyl-1,4,7-triazacyclononane;1,4-bis(pyridyl-2-methyl)-7-ethyl-1,4,7-triazacyclononane;1,4-bis(pyridyl-2-methyl)-7-methyl-1,4,7-triazacyclononane;1,4-bis(pyrazol-1-ylmethyl)-7-octyl- 1,4,7-triazacyclononane;1,4-bis(pyrazol-1-ylmethyl)-7-ethyl-1,4,7-triazacyclononane;1,4-bis(pyrazol- 1-ylmethyl)-7-methyl- 1,4,7-triazacyclononane,3,5-dimethylpyrazol-1-ylmethyl)-7-octyl-1,4,7-triazacyclononane;3,5-dimethylpyrazol-1-ylmethyl)-7-ethyl-1,4,7-triazacyclononane;3,5-dimethylpyrazol-1-ylmethyl)-7-methyl-1,4,7-triazacyclononane;1,4-bis(1-methylimidazol-2-ylmethyl)-7-octyl-1,4,7-triazacyclononane;1,4-bis(1-methylimidazol-2-ylmethyl)-7-ethyl-1,4,7-triazacyclononane;1,4-bis(1-methylimidazol-2-ylmethyl)-7-methyl- 1,4,7-triazacyclononane;and, 1,4,7-tris(quinolin-2-ylmethyl)-1,4,7-triazacyclononane;1,4,7-tris(pyridin-2-ylmethyl)-1,4,7-triazacyclononane.

EXAMPLES

Cobalt(II) 2-ethylhexanoate (65 wt. % solution in mineral spirits) wasobtained from Aldrich.

Dimethyl2,4-di-(2-pyridyl)-3-methyl-7-(pyridin-2-ylmethyl)-3,7-diaza-bicyclo[3.3.1]nonan-9-one-1,5-dicarboxylate(N2py3o-C1) and the iron(II) complex thereof [Fe(N2py3o-C1)Cl]Cl wasprepared as described in WO0248301.

Dimethyl2,4-di-(2-pyridyl)-3-octyl-7-(pyridin-2-ylmethyl)-3,7-diaza-bicyclo[3.3.1]nonan-9-one-1,5-dicarboxylate(N2py3o-C8) and Dimethyl2,4-di-(2-pyridyl)-3-octadecyl-7-(pyridin-2-ylmethyl)-3,7-diaza-bicyclo[3.3.1]nonan-9-one-1,5-dicarboxylate(N2py3o-C18) and the corresponding iron complexes, [Fe(N2py3o-C8)Cl]Cland [Fe(N2py3o-C18)Cl]Cl, were prepared as described in WO 2005042532.

N,N-bis(pyridin-2-yl-methyl)-bis(pyridin-2-yl)methylamine, hereafterreferred to as N4Py, and the corresponding iron(II) complex,[Fe(N4py)Cl]Cl, were prepared as described in EP0765381.

N,N-bis (pyridin-2-yl-methyl)-1,1-bis(pyridin-2-yl)-1-aminoethan,hereafter referred to as MEN4Py, and the corresponding iron(II) comples,[Fe(MeN4Py)C1]C1, were prepared as described in EP0909809.

4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane, hereafterreferred to as Bcyclam, and the corresponding manganese(II) complex,[Mn(Bcyclam)Cl₂], were prepared as described in WO98/39098 and J. Am.Chem. Soc., 122, 2512 (2000)).

N-methyl-trispicen (Metrispicen), N-octyl-trispicen (C8-trispicen),N-octadecyl-trispicen (C18-trispicen) were synthesised according toliterature procedures (Bernal, J.; et al. J. Chem. Soc., Dalton Trans.1995, 3667) and GB2386615. The corresponding iron(II) complexes,[Fe(Metrispicen)Cl]Cl, [Fe(C8-trispicen)Cl]Cl, and[Fe(C18-trispicen)Cl]Cl, were prepared similarly to the proceduredescribed in EP0909809 for the MeN4py analog.

1,4-bis(quinolin-2-ylmethyl)-7-ethyl-1,4,7-triazacyclononane (Quin₂TACN)and the corresponding [Fe(Quin₂TACN)Cl]ClO₄ compound were prepared asdisclosed in EP1259522.

Mn₂ (μ-O)₃ (1,4,7-trimethyl-1,4,7-triazacyclononane)₂, PF₆)₂ wasprepared as published elsewhere (J. Chem. Soc., Dalton Trans, 353(1996)).

Experiment 1 Homogeneous Bleaching of β-carotene in Hexane withMethyllinoleate

This experiment was done to show that the β-carotene can be degraded byinteraction of the various iron and manganese catalysts withmethyllinoleate, as an indicator for radical reactions (which in turnshould lead to increased rate of paint/ink drying).

UV/VIS experiments were performed on a Hewlett Packard 8453 apparatus.All the experiments were performed at 35° C. and measurements wereconducted over a period of 1 hour in the UV/VIS kinetic mode. The assayswere done in a quartz cuvette and were shaken thoroughly before startingthe measurements. The stopper was removed from the cuvettes duringmeasurements.

The hexane solutions contained 85.6 μM β-carotene, 6.0 mMmethyllinoleate, approximately 5 μM of the catalyst and 3.1% (v/v)ethanol. The initial absorbance at 452 nm was about 0.45 A.U. Thedifference between the initial absorbance and absorbance after 600seconds in each case is given in table 1. A higher value indicates ahigher β-carotene bleaching activity.

TABLE 1 Homogeneous bleaching experiments using β-carotene andmethyl-linoleate in combination with 5 μM of each catalyst. ΔA452 nm(600 s) Blank (no catalyst added) 0.01 [Fe(N2py3o-C1)Cl]Cl 0.08[Fe(N2py3o-C8)Cl]Cl 0.11 [Fe(N2py3o-C18)Cl]Cl 0.10 [Fe(MeN4py)Cl]Cl 0.06[Mn(Bcyclam)Cl₂], 0.07 [Fe(Metrispicen)Cl]Cl 0.03 [Fe(C8-trispicen)Cl]Cl0.06 [Fe(C18-trispicen)Cl]Cl 0.08 [Fe(Quin₂TACN)Cl]ClO₄ 0.06Cobalt(II)-(2-ethylhexanoate)₂ 0.01

The results presented in table 1 clearly indicate that the iron andmanganese compounds disclosed in this invention furnish a significantenhancement of β-carotene bleaching with methyllinoleate.

Experiment 2 Drying Time of Linseed Oil Paint

A solvent borne model (linseed oil in n-heptane) is used for alkyd basedsystems. All experiments were performed at room temperature and filmswere made on a petridish. The starting catalyst concentrations that wereused were between 0.016 mM and 0.32 mM as exemplified in Table 2.Co(II)-2-ethylhexanoate (1.63 mM) and a blank (linseed oil/heptane 50/50v/v) were also incorporated for comparison.

The film on the petridish consisted of 100 μl (50/50 v/vlinseed/n-heptane) and 25 μl catalyst solution in ethanol (vide suprafor final concentrations in linseed oil/heptane solutions).

The results of the tested iron and manganese complexes are shown intable. In all cases, the time needed to establish tack-free drying isgiven in the table. Films were classified as tack-free when they gave astraight line when a pin was run through the film, but a fingerprint wasstill visible on the film. Through-dry indicates that the coating washard and no print was visible anymore. A lower value indicates a fasterdrying time. Different concentrations of drying catalysts were taken, toestablish the lowest level that still can attain an equal or betterdrying than the cobalt salt.

TABLE 2 Drying times to need tack free or completely dry linseed paintwith different compounds and levels. Concentration in film Tack Starting(μg/100 μl free drying Concentration linseed) time (h) Blank — — >120Cobalt(II)-(2-  1.63 mM 22 28 ethylhexanoate)₂ [Fe(N2py3o-C1)Cl]Cl 0.064mM 1.0 20 [Fe(N2py3o-C1)Cl]Cl 0.016 mM 0.26 28 [Fe(N2py3o-C8)Cl]Cl 0.064mM 1.2 20 [Fe(N2py3o-C8)Cl]Cl 0.032 mM 0.61 28 [Fe(N2py3o-C18)Cl]Cl0.064 mM 1.4 20 [Fe(N2py3o-C18)Cl]Cl 0.032 mM 0.7 28 [Fe(N4py)Cl]Cl 0.32 mM 4 22 (through dry) [Fe(MeN4py)Cl]Cl 0.064 mM 0.8 20[Fe(MeN4py)Cl]Cl 0.016 mM 0.2 27 [Mn(Bcyclam)Cl₂]  0.32 mM 3.1 20(through dry)

The results presented in the table clearly show that these iron andmanganese compounds are much more active on molar basis than thereference, i.e. Cobalt(II)-(2-ethylhexanoate)₂. Especially[Fe(N2py3o-C1)Cl]Cl and [Fe(MeN4py)Cl]Cl show an improvement of a factorof 100 on molar basis compared to the Co-ethylhexanoate drier.

TABLE 3 Drying times to need tack free or completely dry linseed paintwith [Mn(Bcyclam)Cl₂] and Mn₂(μ-O)₃(1,4,7-trimethyl-1,4,7-triazacyclononane)₂]PF₆)₂ (abbr. as Mn- Me3TACN)Starting Tack free drying Concentration time (h) Blank — >120Cobalt(II)-(2- 1.63 mM  28 ethylhexanoate)₂ [Mn(Bcyclam)Cl₂] 2.5 mM  6(tack free) [Mn(Bcyclam)Cl₂] 0.5 mM 10 (tack free) Mn-Me3TACN 0.5 mM 20(tack free) [Mn(Bcyclam)Cl₂] 0.2 mM 20 (tack free) Mn-Me3TACN 0.2 mM 23(tack free)

The data shown in table 3 show that [Mn(Bcyclam)Cl₂] exhibits asignificantly higher activity than Mn-Me₃tacn, exemplifying that themanganese complex with a tetradentate nitrogen donor ligand shows afaster paint drying activity than a manganese complex containing thetridentate triazacyclononane ligand.

Experiment 3

Storage stability of catalysts in linseed oil paint in the presence of(+)-α-tocopherol (Vitamin E), purchased from Sigma.

The drying activity of the [Fe(MeN4py)Cl]Cl and [Fe(N2py3o-C18)Cl]Clwere monitored in the presence of (+)-α-tocopherol

(Vitamin E)

An oil-paint sample based on linseed was prepared containing 4 mllinseed, 3820 μl n-heptane, 80 μl (10 mM (+)-α-tocopherol in heptane)and 100 μl catalyst solution in ethanol. As a reference an oil-paintsample without (+)-α-tocopherol is included containing 4 ml linseed, 3.9ml n-heptane and 100 μl catalyst solution in ethanol. The oil-paintsamples were stored in closed glass vials under ambient conditions.Films were painted, each with a separate brush, on a wooden board aftercertain storage periods. The drying time was monitored and the resultsare summarised in table 4 and 5.

TABLE 4 Drying activity of 0.004% wt. [Fe(MeN4py)Cl]Cl (0.0004% based onFe metal) in the absence and presence of 0.009% wt. α- tocopherol in theformulation after different times of storage at room temperature. Theamount catalyst dosed is based on the amount in the linseed oil (and noton the linseed oil/heptane mixture). Storage time Without α-tocopherolWith α-tocopherol (days) drying time drying time 0 <20 h <19 h 3 <20 hn.d. 5  25 h n.d. 6 n.d. <22 h 10 >30 h; <46 h n.d. 11 n.d. >24 h; <28 h

TABLE 5 Drying activity of 0.006% [Fe(N2py3o-C18)Cl]Cl (0.0004% based onFe metal) in the absence and presence of 0.009% α- tocopherol in theformulation after storage at room temperature. The amount catalyst dosedis based on the amount in the linseed oil (and not on the linseedoil/heptane mixture). Storage time Without α-tocopherol Withα-tocopherol (days) Tack free drying time Drying time 0 22 h 22 h 3 24 hn.d. 5 25 h n.d. 6 n.d. 22 h 10 30 h n.d. 11 n.d. 22 h

The results shown in tables 3 and 4 indicate that the presence ofα-tocopherol retards the decreased linseed oil drying activity of thecatalysts.

Experiment 4 Storage Stability of Catalysts in Linseed Oil Paint UnderNitrogen vs Atmospheric Conditions

Oil-paint samples based on raw linseed oil and n-heptane were preparedin glass vials (50/50 v/v) and stored under nitrogen. [Fe(MeN4py)Cl]Clwas present in 0.004 weight % (0.0004% based on Fe metal)—added as asolution in ethanol and α-tocopherol was present in 0.009 weight %(added as a solution in n-heptane). The level dosed of [Fe(MeN4py)Cl]Clis based on the weight of the compound. Similarly, experiments wereconducted using 0.005% [Fe(N2py3o-C1)Cl]Cl (0.0004% based on Femetal)-added as a solution in ethanol. The amount catalyst dosed isbased on the amount in the linseed oil (and not on the linseedoil/heptane mixture). The oil-paint samples were purged with nitrogenevery time the glass vials were opened. After certain storage periodsthe samples were painted on a wooden board and the drying time wasmonitored. The drying times are summarised in table 6 and 7 for[Fe(MeN4py)Cl]Cl and [Fe(N2py3o-C1)Cl]Cl respectively.

TABLE 6 Drying activity of 0.004% [Fe(MeN4py)Cl]Cl (0.0004% based on Femetal) stored under ambient atmospheric conditions and under nitrogen.The amount catalyst dosed is based on the amount in the linseed oil (andnot on the linseed oil/heptane mixture). Entries 2 and 4 show the timesneeded to achieve drying in the presence of 0.009% α-tocopherol in theformulation. Stored under ambient Storage atmospheric conditions Storedunder nitrogen time (days) Drying time drying time  0 (without <20 h Notdetermined tocopherol  0 (with <19 h Not determined tocopherol) 30(without More than 32 h, but 29 h tocopherol less than 47 30 (with Morethan 30 h, but 29 h tocopherol) less than 46 h

TABLE 7 Storage stability of 0.005% [Fe(N2py3o-C1)Cl]Cl (0.0004% basedon Fe metal) stored under ambient atmospheric conditions and undernitrogen. The amount catalyst dosed is based on the amount in thelinseed oil (and not on the linseed oil/heptane mixture). Entries 2 and4 show the times needed to achieve drying in the presence of 0.009%α-tocopherol in the formulation. Stored under ambient Storageatmospheric conditions Stored under nitrogen time (days) Drying timeDrying time  0 (without <19 h Not determined tocopherol  0 (with <19 hNot determined tocopherol) 30 (without  32 h 24 h tocopherol 30 (with 28 h 26 h tocopherol)

The results in table 5 and 6 illustrate that nitrogen also retards thedecreased linseed oil drying activity of the catalysts.

Experiment 5

Storage stability of catalysts in linseed oil paint in the presence ofethylene glycol.

Oil-paint samples based on linseed and n-heptane (700 l; 50/50 v/v) wereprepared containing 0.005% [Fe(MeN4py)Cl]Cl (0.0005% based on Fe metal)added as a solution in ethylene glycol (100 μl). The tack free dryingtime of this sample is compared with the tack free drying time of asample to which 0.005% [Fe(MeN4py)Cl]Cl (0.0005% based on Fe metal) isadded, as a solution in ethanol (table 7). The amount catalyst dosed isbased on the amount in the linseed oil (and not on the linseedoil/heptane mixture).

After certain storage periods the samples were painted on a wooden boardand the drying time was monitored (table 8).

TABLE 8 Storage stability of 0.005% [Fe(MeN4py)Cl]Cl (0.0005% based onFe metal) in dissolved in ethanol (left) and ethylene glycol (right) andadded to the linseed oil after different times of storage at roomtemperature. Catalyst dissolved in Catalyst dissolved in Storage ethanolTack ethylene glycol time (days) free drying time Tack free drying time0 <20 h <16 h 31  29 h <20 h

The data shown in table 7 clearly show that the presence of ethyleneglycol over ethanol largely retards the decreased linseed oil dryingactivity.

1. A curable liquid medium comprising: a) from 1 to 90 wt % of analkyd-based resin; and, b) from 0.0001 to 0.1 wt % of a siccative,wherein the siccative is an iron or manganese complex of a tetradentate,pentadentate or hexadentate nitrogen donor ligand, wherein the ligandis:

wherein each R¹, R² independently represents —R⁴—R⁵, R³ representshydrogen, optionally substituted alkyl, aryl or arylalkyl, or —R⁴—R⁵,each R⁴ independently represents a single bond or optionally substitutedalkylene, alkenylene, oxyalkylene, aminoalkylene, alkylene ether,carboxylic ester or carboxylic amide, and each R⁵ independentlyrepresents an optionally N-substituted aminoalkyl group or an optionallysubstituted heteroaryl group selected from pyridinyl, pyrazinyl,pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyland thiazolyl.
 2. The curable liquid medium according to claim 1,wherein the ligand is selected from the group consisting ofN,N-bis(pyridin-2-yl-methyl)-bis(pyridin-2-yl)methylamine andN,N-bis(pyridin-2-yl-methyl-1,1-bis(pyridin-2-yl)-1-aminoethane.
 3. Thecurable liquid medium according to claim 1, wherein the iron ion isselected from Fe(II) and Fe(III) and the manganese ion is selected fromMn(II), Mn(III), and Mn(IV).
 4. The curable liquid medium according toclaim 1, wherein the siccative is an iron (II) or iron (III) complex. 5.The curable liquid medium according to claim 1, wherein the siccative isan iron (II) complex.
 6. The curable liquid medium according to claim 1,wherein the content of the siccative is between 0.0001 and 0.05% w/w. 7.The curable liquid medium according to claim 1 further comprisingbetween 0.001% and 0.1% of at least one antioxidant selected from thegroup consisting of di-tert-butyl hydroxy toluene, Ethoxyquine,α-tocopherol, and 6-hydroxy-2,5,7,8-tetra-methylchroman-2-carboxylicacid.
 8. The curable liquid medium according to claim 7, wherein thecomposition comprises between 0.002 and 0.05% of at least oneantioxidant.
 9. The curable liquid medium according to claim 7, whereinthe antioxidant is α-tocopherol.
 10. The curable liquid medium accordingto claim 1, containing between 0.001 and 90% of ethylene glycol,diethylene glycol, dipropylene glycol, glycerol, pentaerythritol,dipenta erythritol, neopentyl glycol, trimethylol propane, trimethylolethane, di-trimethylol propane and 1,6-hexane diol.
 11. The curableliquid medium according to claim 10, containing between 0.1 and 50% ofethyleneglycol or glycerol.
 12. The curable liquid medium according toclaim 10, containing between 0.3 and 5% of ethyleneglycol or glycerol.13. The curable liquid medium according to claim 1, containing between0.001 and 2.5% of lead, zirconium, bismuth, barium, vanadium, cerium,calcium, lithium, strontium, and zinc.
 14. The curable liquid mediumaccording to claim 1 when cured.